The present invention relates to a color image processing apparatus which is peculiarly well fitted for an image processing apparatus such as a color copier in which a plain paper is used as a recording paper. The invention especially relates to a color image processing apparatus in which the region designating information can be accurately detected.
In a color image processing apparatus such as a color copier in which laser beams are used, color image information is obtained by dissolving plural colors on a color document, and color images are recorded according to the color image information.
A color copier of this kind is designed and made so that it can conduct various image processes such as variable magnification processing and partial color conversion processing.
With partial color conversion processing an image compiling process in which the color image information inside or outside the designated region can be recorded by the color by which the region is designated.
Designation of the region is usually conducted by a color marker. For instance, when the region a is designated by a blue marker as shown in FIG. 20A, the image within the region a is recorded by the color which was used to designate the region, which is blue in this example. Refer to FIG. 20B.
If the image in another region can be erased, the images in the region can be recorded as black and white images.
In order to attain the partial color conversion mode, it is necessary to detect the color of a color marker used to designate the region. As shown in FIG. 21, the marker signals BP, RP are detected from the color marker with scanning lines (n, n+1, and so forth) and at the same time the region signals OB', QR' are generated by the process.
According to these marker signals BP, RP and the region signals QB', QR', the images in the designated region are extracted and recorded and the recording process shown in FIG. 20B is attained.
To change the subject slightly, in this type of color image processing apparatus equipped with the partial color conversion processing function, the apparatus can not convert colors within the designated region correctly unless the image information of a document and that of a color marker are discriminated accurately.
Especially when a color marker and document image overlap, for instance, when a black longitudinal or lateral ruled line crosses the image, the color marker is drawn on the ruled line. As a result, the information obtained is not color marker information, but document image information.
For example, at the position where the black ruled line and the color marker cross as shown in FIG. 22A and FIG. 22B, the color mark's information is obtained in the edges of both sides of the crossing area contour, but the color mark information can not be obtained within the crossing area.
Accordingly, the color marker information is broken off at this crossing area and the color conversion processing is not properly conducted there.
According to the present invention, a color image processing apparatus is equipped with a partial color conversion processing function, which can detect the color marker accurately.
In order to solve the problems mentioned above, the present invention has the following characteristics. A color image processing apparatus in which color image information converted to an electric signal is processed, comprises a color discriminating means; a color ghost correction means; an image processing means by which an image processing of a designated region is conducted according to color information different from the color of a document to be read out and at least a part of the color information of the document which comes into contact with the region designating color information, is changed to the color information to designate the region. Another characteristic of the image processing apparatus of the present invention is explained as follows. In the image processing apparatus mentioned above, the document color information sandwiched between the color information which designates the region, can be changed to the information to designate the region.
The marker correction circuit 600 is installed in order to accurately detect the color marker region. Refer to FIG. 12.
In the marker correction circuit 600, the image data of a single pixel which corresponds to several pixels or several lines, is referred. If the color information comes into contact with the color marker information to designate the region, this color information is changed to the color marker information. In other words, data is replaced. Furthermore, when there exists document color information sandwiched between the color marker information, the sandwiched document color information is changed to the color marker information.
For the purpose of processing data as explained above, the color information correcting table is provided in the marker correction circuit 600. When the color information combined as explained above, is input, the target pixel is changed to the color information of the color marker. Refer to FIG. 10.
After the target pixel is changed to the color information of the color marker, even in the case when the image information of the document crosses the color marker, the color marker data does not break. Therefore, the designated region can be accurately detected.